The invention relates to an apparatus for improving preconditioning of the fuel-air mixture in the induction tube of a mixture-compressing and externally ignited internal combustion engine with an arbitrarily actuated throttle device which cooperates with a coaxial preconditioning device also located in the induction tube and pivoting due to the force of the aspirated air against a restoring force.
In well-known fuel supply systems of this kind, the preconditioning of the fuel-air mixture within the suction tube is satisfactory only in certain specific regions of the revolutions per unit time or of the load conditions. Only within these regions wherein a thorough mixing of the air and the fuel takes place, and wherein, moreover, the fuel is finely vaporized, is a homogeneous mixture guaranteed for all the cylinders of the engine. However, within the other regions the cylinders of the engine receive a mixture that is too lean or too rich, resulting either in an unstable running of the engine, or in an especially high proportion of noxious exhaust gas constituents. Therefore, the danger exists, especially at full load, that an unsatisfactory precondition and distribution of the mixture will occur due to excessively low air velocities in the aspiration tube.